Pole piece



Oct. 10, 1933. g MUDGE 1,929,787

POLE PIECE Filed Jan. 18, 1930 Patented Oct. 10,1932" I s p 1 929 731 r OLE es t .7 si Charles A. Mirage;- Elizabeth, N. J., a ssignor to E f Electro Dynamic company, Bayonne, --N." J., a \corporation o f New Jersey s t I e ApplicfatioirJahliq y 18, on." "seria 1%, 2 6 7 v '1 5 i m -1 5 a. i I V e v .l This invention relates fprirnarilyito teale65 belobserved that theilaniinations rnay ,be made struction or pole pieces ingeneral, andmorelplarto overlap in :askewed arrangement so that; for tigularly to such' pole piecesgas are usedsonwdy- I example, the cross-sectionis somewhat diamond namo electric machines. The principlesof the shaped. The notches register, whether the pieces 6 present invention tare alsoapplicable. tojother are skewed or, straight. i 1: .r 7. 3 1 e 51) ma netic orelectrormagnetie structures. e r I Obviously; the laminationsrshown insideiele- "It is customary to make the polesyof dynamo vation .Figure 1 may be; skewed with respect elegtrio machinesofiethin laminations chiefly in to eachother, so that both the ecor'eand the shoe d r t s ed the eddypufrentlgsses therein; are skewed; This 'is. possible becausei'the two 1 It is oneofthe objectsof the present invention surfaces, namely; the pole shoe surface 5, fee;- 35' to provide an improved "method .and means for ing the armature andptheend surface 6; which is securing the laminations together without the secured inside ofthe field yokeyring;arercoaxial use-oirivets, therebyobviating the necessity for cy in i ls fa fi wev k W e f' rivetholes in the laminationsand'saying in the the entire-pole piece results in 'a diamond shaped 1g cost-pf the dies and in 'the'maintenancej there c01' e se'ctioniwhichcalls fora special shaped coil. 2m

-. 29 preferably, although'not necessarily, secured ,to-

2 ,The attai mentr th ab ve andotherobjects 1 3b the drawing tionsimperforate and securing them together b poleshoeis sliowriin Figures 5 ands. A U y s welding. Where the pole piece comprises iawsolid 7 :Two? separate laminations areformed;;namel'y,

core-and laminated poleshoes the pole shoes arethe laminations 2-,-A-forming the;corevportio n l and the ,laminations 1o ,;A, uforming the oe, 1 ggther by welding 'and a rejth e n lde t phej orwtip rportion. l -The upper and lowenends &.of s polecore. ,I do notint'endjto be limitedto the the coresportionxiieveAxare cution coneentricscirparticular method herein idisclosedialthough-it iclesjto-e-givesthe oylindrical edges. 6 and7.L{i-.The has advantages over other methods. top and-bottom edgesfof the pole shoe portion 10,-:,A, alie 'likewiseicut on concentric circles to 80' of a the present inventioiiwill be apparentlfmm v provide the cylindrical top: and bottom: edges thefollowingspecification takenrin conjunction.v 8 and?) which aretcoaxiali with the edges 7 "and withtheaccompanying drawingforminga part figof thecore portion; thereof. i t i mThe ,laminations 10-A are assembled :in

of. This is ,accomplished hymaking the lamina Theipreferredgmethod.of.securing the skewed 4 1 V skewedrelationgas may be seen in Figures "5 Figural is nd-view f'a; polepieogfor a andfi, and are compressed and joined together dynamo electric .maohine; constructed in'aecord in' such skewed relation by the lineoflwelding arise with my invention; indicated; at-1l.'7A.and 121-A, therebytholding Figure2 is a side view lof the poleopiece; I the laminations of, the;tip, or shoe portion, firm;

35 7 Figure 3 is an endwiew of a'modifiedlform ,of lytoge ther; Likewise, the laininations for thee! pole piece; J V, v core portion are compressed andiweldedalon g Figure 4 is an endviewofastill difierentcom, the lines ".ofewelding 44. A line :of: welding struction; s' n 1 .14 A"lthen'jpins the pole core. portionZ-i-Awith Figure 5 is a sideeelevation of a modifiedform the tip portion '10,A. This leaves the'p'ol'e por- 40 of; a pole piece employing a skewed-pole shoe, tionjZ-I A rectangular in cross seetion to re- 95 d n t k 'ceivethe core, and makesthe 'pole'shoe skewed Figure 6 3,1 1 D 1; v lew ot the Sande, to provide noiseless operation of the motor a's' Referring now more particularly tothe conwell as" to provide a more uniform torque on structionshowii in Figures land? the .pole, piece the periphery "of the armature; Thereby, the

; comprises a nui'nber of thi'n, fflat, impertorat'e conductors jo'n the armature cut-into the pole 1'00 7 larninations if, having a core, ition"21 and a flux more unirormiy; or gradually give a; uniform pole shoe portion 3 integral therewith, Each of inerease'of v oltageas measuredfrom barto bar the laminationsil has a nurnb'e'rjof notches 4 on the'commutator. v If i 7 formed -therein 1 durin g 'the,;punehing of; the lnsteadof forming'the'pole poi'tion-2A of metal, The 'laminations, which are identical, are laminationsgit frnaylb'e for ned of "a {solidpiece T05 stacked oneupon another in a suitable assembly as shown in Figures 3"'andj'4.' In-thatcase the fixture to bring them into the desiredfre'gister' pole shoe laminat'iohs are assembled and Welded with each" other and are then 'con'ipressedand' :togietheriri skewed relation and then-the solid weldedtogether as by depositingwelding'metal 'pole' piece "is}pre'ssed against the top surface-8 I While the welding may be done in any desired manner I prefer to use a metal electrode and form a line of welding in the groove formed by the registering notches 4 in the laminations. The welding metal preferably falls short of filling the groove. It is possible to weld the laminations together in any other known manner. I prefer to use the ordinary process of arc and metal electrode, progressively forming the weld in the groove. Gas welding may be employed. The welding acts as a bond on the surface of the laminations and, from tests, has been found to be a perfectly satisfactory means for securing the laminations together;

The welding metal may be made of relatively high resistance and relatively low reluctance. By depositing the weld in the grooves the advantage of accurate location is secured and the further advantage of leaving the face of the core without any projections which would interfere with mounting the field pole winding thereupon.

' It' is, in fact, easier to weld the parts together than it is to pass. a number of rivets through perforations in the pole pieces and then rivet them up as is donein the prior art. My process leaves no projections anywhere and hence the field spools may be made to fit snugly and at the same time are easily adjusted into place. 7

Pole pieces are sometimes made with a solid core structure and a laminated pole shoe structure. Such an arrangement is shown in Figures 3 and 4. The pole shoe 10 of Figure 3 comprises a number of thin laminations, each comprising a sheet. metal stamping having two rows of notches 11 and 12 formed therein during the stamping process, these notches registering to form transverse grooves.

The. laminations are piled on top of each other either in accurate register or skewed if desired, compressed, and welded together by means of an arc and a metal electrode which fills the groove formed by the rows of notches 11 and 12. Each of the laminations 10 is also provided with another pair of notches 13 and 14 likewise formed during the punching process. When the pole shoe has been assembled and the laminations welded together, the assembled pole shoe is pressed and held against the end of a solid core 15 and it is welded thereto at the indentations 13 and 14 by means of a metal electrode in the same manner that the laminations were secured together.

The edges of the core 15 may be chamfered oil so that the lines of "welding metal 13--14 may be deposited below the projected planes. of the adjacent surfaces of the pole piece 15, and shoe 10. Thus no interference with the spool of the spool of the field winding is caused. It will be observed that the cross section of the weld is small and is very definitely controllable.

If desired the laminations of the pole shoe may be secured together by means of rivets 18 and 19 as shown in Figure 4 and then welded to the solid core structure 15 in the same manner that the assembled pole shoe of Figure 3 is welded to the core.

In such a construction thelaminations comprising thepole shoe are of course provided with perforations for receiving the rivets l8 and I do not intend to limit the invention to the Y exclusive use of welds for holding the laminations together whether the, pole be formed completely of laminations, as shown in Figures 1 and 2 or partially as shown in Figures 3 and 4.

The laminations comprising the pole shoes of Figures 3 and 4 may be made of sheet strip steel rather than out out of a big plate, and consequently the cost of the die for the laminated part would be much less than if the whole section of the pole were made by the die.

It will be observed that the welds are formed on the back side of the laminated pole shoes 10 and hence are in better location with respect to fiux pulsations than any rivets such as 18-l9 can be.

The method of securing the edges together perm-its a greater freedom of design Without added cost, as a rectangular or skewed pole or shoe may be made from identical stampings merely by the manner of assembling.

After the pole pieces are formed as shown they are drilled and tapped at their upper ends for receiving cap screws or studs to fasten them into a field frame, as disclosed in my copending application Serial No. 421,991, filed January 20, 1930.

Welding at the edges is a highly satisfactory method because the edges are clean freshly cut metal. The notches providing the grooves are formed preferably bythe same operation whereby the individual stampings are punched out, or may be cut afterwards either by separate operations on the plates or by cutting a groove in a group of assembled punchings.

While I have herein shown and described a few preferred embodiments of my invention, it is to be understood that the invention is not limited to the precise constructions herein shown, the same being merely illustrative of the invention.

What I consider new and desire to secure by Letters Patent is:

1. In a dynamo electric machine, a pole comprising a core portion and a laminated pole shoe, the laminations being welded together and welded to the core portion.

2. A pole piece of the type adapted to receive a magnetizing winding thereon, said pole piece comprising a laminated core portion having a pole shoe at one end and adapted to receive the winding over the other end, the laminae having registering notches at their edges to form grooves extending across the core portion, said lamina: being welded together across their edges by metal deposited and lying substantially entirely within the grooves, the outer surface of the-welded metal being substantially flush with s the outer surface of the core whereby the welded metal does not increase the outer dimension of the core around which the magnetizing winding is placed.

3. A pole piece of the type adapted to receive a magnetizing winding thereon, said pole piece comprising a laminated core portion having a pole shoe at one end and adapted to receive the winding over the other end, the lamina: having registering notches at their edges to form grooves extending across the core portion, said laminae being welded together across their edges by metal deposited and lying substantially entirelywithin the grooves, the outer surface of the welded metal being substantially flush with the outer surface of the core whereby the welded metal does not increase the outer dimension of the core around which the magnetizing winding is placed, the pole shoe of the pole piece com- M prising a laminated structure with the laminae welded together and. to'the core. p

4; A pole piece of the type adapted to receive a magnetizing winding thereon, said pole piece comprising a laminated core portion having a pole shoe at one end andadapted to receive the Winding over the other end; the laminmhaving registering notches at their edges to form welded metal being substantially flush with the (iii grooves extending across the core portion, said laminae being welded together across their edges by metal deposited and lying substantially entirely within the grooves, the outer surface of the outer surface of. the core'whereby thewelded metal does not increase the outer dimension of 'thecore'around which the magnetizing winding is placed, the pole shoe extending laterally of the core, and the laminae of the pole shoe being welded-together at thelaterally extending portions thereof. a

receive the winding over one end, each lamina having a. pole shoe portion formed integrally therewithat the other end, the. lamina: having registering notches at their edges to form grooves extending across the'core portion, said lamina: being welded togetheracross their edges' by metal deposited and lying substantially entirely' within the grooves, the outer surface of the welded metal being substantially flush with the outer surface of the core whereby'the welded metal does not increase the outer dimension of i 1 which the magnetizing winding the core around is placed. n a a y CHARLESA. MUDGE. 

